This invention relates to the packaging and subsequent removal of material that tends to stick to the inside perimeter of containers and to thereby prevent viewing of the contents inside the containers. The invention is particularly applicable when such attachment of particles to the container sides is due primarily to electrostatic forces. Many particulate materials are packaged and shipped in plastic, glass, or similar smooth-sided containers. When human users dump or other-wise transfer particle contents from a nearly transparent shipping container, the common experience is a desire to see inside the container in order to see how much of the contents have been removed. If the intent is to remove all of the contents, then such viewing is to see whether all contents have been removed. However, if a thin layer of particles have attached themselves to the inside walls of the container, then such viewing is made difficult or impossible. The problem becomes more frustrating when the particulate matter is light-weight and, accordingly, difficult to determine by heft whether the contents have been dumped. Even more frustration occurs when the container is first fastened to a receiving receptacle before the contents are removed. Since the container is fastened in place, its heft cannot be easily determined. Although containers filled with other particulate or granulated products may benefit from the present invention, including without limitation, pelletized or granulating marking materials such as waxy inks, the invention will be explained in reference to electrophotographic toners, or other dry inks and marking materials. Typical electrophotographic toners are stored and transported in nearly transparent plastic bottles. The process of transferring toners from such toner bottles or cartridges occurs after the bottle has been affixed to a receiving receptacle The toner particles themselves are light and fluffy. Moreover, toner particles are designed to readily accept electrostatic charges. Hence, the agitation and shaking of toner bottles that is recommended prior to loading the cartridges onto printing machines typically induces charges in the particles that cause at least a thin film of particles to adhere to the inside walls of their containers. The combined result is that it is very difficult to determine whether all the contents of a toner bottle have been transferred from the toner bottle to the receiving receptacle of a printing system. Many user observations document users attempting to shake, tap, and otherwise agitate the bottle while it is fastened to the printing machine. Users also commonly attempt to peer into the battle. All these are attempts to ensure that the contents of the bottle have transferred. And for the reasons described above, most users who attempt such verification are unable to make the determination. Observations confirm persistent user frustration at not being able to visually or manually detect whether all toner particles have been transferred.
The following is a background description of the nature of electrostatic toners: Generally, in the process of electrostatographic printing, a photaconductive insulating member is charged to a substantially uniform potential to sensitize the surface thereof. The charged portion of the photoconductive insulating member is thereafter exposed to a light image of an original document to be reproduced. This records an electrostatic latent image on the photoconductive insulating member corresponding to the information areas contained within the original document. Alternatively, in a printing application, the electrostatic latent image may be created electronically by exposure of the charged photoconductive insulating member by an electronically controlled laser beam or light emitting diodes. After recording the electrostatic latent image on the photoconductive insulating member, the electrostatic latent image is developed by bringing a developer material charged of opposite polarity into contact therewith. In such processes the developer material may comprise a mixture of carrier particles and toner particles or toner particles alone (both these single component and dual component development systems shall hereinafter be called xe2x80x9ctonerxe2x80x9d). Toner particles are attracted to the electrostatic latent image to form a toner powder image that is subsequently transferred to a copy sheet and thereafter permanently affixed to the copy sheet by fusing.
In such printing machines, the toner material is consumed in a development process and must be periodically replaced within the development system in order to sustain continuous operation of the machine. Various techniques have been used in the past to replenish the toner supply. Initially, new toner material was added directly from supply bottles or containers by pouring to a developer station located within the body of an automatic reproducing machine. The addition of such gross amounts of toner material altered the triboelectric relationship between the toner and the carrier in the developer station, thereby resulting in reduced charging efficiency of the individual toner particles and accordingly a reduction of the development efficiency when developing an electrostatographic latent image on an image bearing surface. In addition, the pouring process was both wasteful and dirty in that some of the toner particles became airborne and would tend to migrate into the surrounding area and other parts of the machine. Accordingly, separate toner hoppers with a dispensing mechanism for adding the toner from the hopper to the developer station in the printing machines on a regular or as needed basis have been provided. In addition, it has become common practice to provide replenishment toner supplies in a sealed container that, when placed in the printing machine, can be automatically opened to dispense toner into the toner hopper. In some of these designs, the toner cartridge may itself serve as the toner hopper. After this type of toner cartridge is mated to the printing machine at an appropriate receptacle, mechanisms are inserted into the toner cartridge that serve to transport the toner from the toner cartridge into the developer station or an intermediate toner hopper on a regulated basis. See, U.S. Pat. No. 5,903,806 issued to Matsunka et al.; U.S. Pat. No. 5,678,121 issued to Meetze et al.; and U.S. Pat. No. 5,495,323 issued to Meetze. In other designs, the toner cartridge is mated to the appropriate receptacle of the printing machine and then toner is dumped all at once from the toner cartridge into a toner hopper within the printing machine. Such toner in the hopper is then drawn into the developer station on a regulated basis. The toner cartridge, once its contents are dumped, is removed from the receiving receptacle and is either discarded or recycled.
In any design utilizing a customer replaceable toner cartridge for replenishment, one difficulty that arises is ensuring that all toner has been removed from the cartridge. This difficulty has two aspects: First, as described above, it is difficult to detect whether all toner has been removed from the cartridge. This is partly because toners in small quantities weigh little and are therefore difficult to detect by sensing their weight. More importantly, toner particles are designed to efficiently accept electrostatic charges with the result that they typically coat the inside surfaces of toner cartridges, thereby making the cartridges opaque.
The second difficulty in ensuring that all toners have been removed from a toner cartridge is the tendency of toner particles settle and clump during shipment and storage. This clumping phenomenon is caused for a variety of reasons: 1) particles of smaller size can fill and pack spaces between larger particles: 2) toner particles are often tacky; and 3) the electrostatic properties of toner particles enable charge attractions between particles. The result is often agglomerations, or clumps, of particles within the toner cartridge. These agglomerations often compact and form bridging structures within the toner cartridge, and such bridging structures adhere to the sides of the toner cartridges. Simple probes and augers as disclosed in patents such as U.S. Pat. No. 5,903,806 issued to Matsunka et al., U.S. Pat. No. 5,678,121 issued to Meetze at al., and U.S. Pat. No. 5,495,323 issued to Meetze may penetrate such agglomerations and bridging structures but do not break them up. Even rotation of the cartridges after mating onto a printing machine toner receptacle does not impart enough energy to shake the clumped toner particles apart from its various clumps and bridging structures. Since toner cost is a major component of the total cost of printing, any significant amount of toner left in a toner cartridge significantly increases the effective cost of using the printer. Worse, customers that do not receive the expected print volume from a cartridge and that cannot see whether a cartridge has in fact been emptied may assume that the cartridge is faulty and make a warranty claim. In other cases, such customers have been known to make a service call that consumes valuable service and technician time.
In response to the above problems related to removal of substantially all toner from toner cartridges, various devices and procedures have been developed to aid the flow and removal of toners from toner cartridges. One effective procedure when performed correctly is simply the shaking or other agitation of a toner cartridge by human operators prior to mating the cartridge with the printing machine receptacle. However, while such agitation if done correctly usually solves the root problem of breaking apart clumps and bridges, it exacerbates the second problem of poor visibility by increasing electrostatic charges attracting a layer of toner to walls of the cartridge. Moreover, much experience confirms that many operators do not read the instructions and do not know or remember that toner cartridges need to be shaken. Even when operators read instructions, humans inevitably interpret product instructions subjectively such that an instruction to xe2x80x9cvigorously agitatexe2x80x9d a cartridge may lead to too much force by a few operators and too little by others. In the absence of being able to see whether in fact all of the toner has flowed out of the cartridge, the result is that some cartridges are shaken or pounded hard enough to be damaged while others are not shaken enough to break up clumps and bridges that may have formed. Once the cartridge is mated to the receiving receptacle while the operator is uncertain whether toner particles remain clumped and bridged, the operator is left with several choices: One is to leave the cartridge as is and to risk wasting toner and/or believing that the printing system is consuming too much toner. A second choice is removal of the cartridge with its seals open, thereby risking contaminating the toner itself plus spilling the difficult-to-clean particles. A third choice is to try to strike, squeeze, or otherwise agitate the toner cartridge in situ. In addition to the probability that some toner nevertheless remains within the cartridge, such agitation in situ risks damage to the mating receptacle and associated parts of the printing machine. The end result is a frequent waste of valuable toner and a resulting increase in the costs of operating the printing machines plus the risk of warranty and service events.
Manufacturers of printing and other systems understand that human operators do not always follow instructions or perform the instructed activities correctly. In effect, humans are inherently uncontrollable elements when asked to perform control processes. Accordingly, a number of solutions have been developed to more fully automate removal of toner from toner cartridges. For toner cartridges that are mounted onto printing machines in order that toner be extracted in a regulated fashion, such cartridges are now often cylindrical in shape with spiral ribs located on the inside peripheral walls of the cartridges. An example of such prior art cartridges is shown in U.S. Pat. No. 5,495,323 issued to Meetze incorporated and is hereby incorporated by reference. See also, U.S. Pat. No. 5,903,806 issued to Matsuoka et al. and U.S. Pat. No. 5,576,816 issued to Staudt et al. that both disclose substantially cylindrical toner cartridges having on their peripheral surface a spiral groove. The toner cartridge and the receiving apparatus operate to rotate the cartridge and to thereby transport the toner within the spiral groove. The apparatus includes a supplying element in the form of an opening and a regulating device. Although toner cartridges with such spiral grooves are effective in urging toner toward the mouth of the cartridge, such grooves by themselves do little to break up the clumps or bridging described above. Even when the apparatus includes a probe, auger, or similar device that penetrates the stored toner in a cartridge, current designs place such probes only along the central axis of the cartridge. Toner clumped or agglomerated along the periphery of the toner cartridge may not be jostled or mixed by either the rotation of the cartridge or by the probe itself. Without the ability to see into the cartridge, an operator often remains uncertain whether all toner has been removed.
At least one prior art device employed a helical member such as a spring inside the toner cartridge for the express purpose of breaking up clumps, bridges, and other agglomerations. In U.S. Pat. No. 4,739,907, issued to Gallant, a cylindrical toner cartridge includes a dispensing opening at one end and an integral toner transport, mixing, and anti-bridging member rotatably supported within the container. The transport, mixing, and anti-bridging member comprises a first coiled spring element having a cross section substantially the same as the cross section of the cartridge and freely rotatable therein, which spring is wound in the direction to transport toner along its length toward the dispensing opening. The member also comprises a second coiled spring element having a cross section substantially smaller than the first spring element but being substantially concentrically positioned and being attached to the first spring element but wound in a direction opposite to the first spring element. In this manner, rotation of the cartridge while the spring members remain substantially fixed results in the scraping of clumped toner from the sides of the cartridge and mixing and penetration of any agglomerations and bridges within the interior of the cartridge by the inner spring.
One limitation to the above prior art cartridges and devices is that each is designed to work in or in conjunction with toner cartridges that rotate once mated to a toner receptacle on the printing machine. Without rotation of the cartridge, neither spiral grooves nor fixedly located springs actively engage toner particles within the cartridge. Additionally, recent advances in imaging and toner production has led to smaller toner particles that now may average less than 10 microns. In order to overcome electrostatic forces that tend to attract particles together and to the toner cartridge itself, a substantial amount of agitation and aeration of the toner particles is preferred. Such agitation, as explained above, exacerbates the inability to see into the cartridge. It would be advantageous, therefore, to devise a toner cartridge assembly that cleans at least a small region of the cartridge sufficiently to enable a human operator to peer inside the cartridge.
Although the above background for the present invention and several of its embodiments are explained in relation to toner cartridges, the present invention is believed to have wide applicability to any container of material, especially particulate or granulated matter prone to settle and clump or materials prone to congeal during storage or handling and that need to be completely removed thereafter from their container.
One embodiment of the present invention is a mechanism for increasing visibility through a portion of the inside surface of a container that holds particulate matter, comprising: (a) a drive mechanism having a movable member positioned to be moved by the drive mechanism along the inside surface of the container; (b) a cleaning member, connected to the movable member and positioned to travel proximately to the inside surface of the container when the movable member is moved; and (c) a switching mechanism, cooperating with the drive mechanism, for activating movement of the movable member by the drive mechanism.
Another embodiment of the present invention is a process for increasing visibility through a portion of the inside surface of a container that holds particulate matter, comprising: (a) connecting a cleaning member with a movable member of a drive mechanism; (b) positioning the movable member such that the connected cleaning member moves proximately to the inside surface of the container when the movable member moves; and (c) activating the drive mechanism to move the movable member.
Yet another embodiment of the present invention is a cartridge for storing marking materials, said cartridge having an inside surface, comprising: (a) a drive mechanism having a movable member positioned to be moved by the drive mechanism along the inside surface of the cartridge; (b) a cleaning member, connected to the movable member and positioned to travel proximately to the inside surface of the cartridge when the movable member is moved; and (c) a switching mechanism, cooperating with the drive mechanism, for activating movement of the movable member by the drive mechanism.